1. Field of the Invention
This invention relates generally to non-abrasive cleaning devices used to clean probes of a testing device in a testing system.
2. Related Art
Microelectronic testing systems may generate erroneous results if probes are not relatively clean while testing. Some probe cleaning devices include a substrate with gel layer. The probes are inserted into the gel layer and the gel removes particles on the probes. However, this probe cleaning device may not completely clean the probes. To solve this problem, other probe cleaning devices have added an abrasive layer between the gel layer and the substrate. The abrasive layer causes the probes to move laterally after passing through the gel, which results in a more thorough cleaning of the probes.
While the use of the gel layer or the gel and abrasive layers solves one problem, the use of a gel having a clear surface creates another problem. First, regardless of whether the surface of a gel layer is clear, translucent, opaque, or something in between, it is difficult for a camera to automatically focus on the topmost clear surface of a cleaning device. For example, the camera may focus on an underlying substrate layer or an abrasive layer in the cleaning device. This is significant because the automatic focus operation of a camera is often relied upon to position a cleaning device relative to probes at the initiation of a cleaning cycle. To account for the actual location at which the camera focuses, a human operator may enter a number corresponding to the gel layer or gel and abrasive layer thickness. Basically, an educated guess or manual measurement is made as to the thickness of the gel layer or gel and abrasive layers and a tolerance factor is entered into the testing system. If the thickness or tolerance factors are off, the probes can be damaged during cleaning. Further, the inputting of such thickness and/or tolerance values for different types of cleaning devices is time consuming and expensive.